org.eigenbase.rel
Class SamplingRel

java.lang.Object
  org.eigenbase.rel.AbstractRelNode
      org.eigenbase.rel.SingleRel
          org.eigenbase.rel.SamplingRel

All Implemented Interfaces:

Cloneable, RelNode

public class SamplingRel
extends SingleRel

SamplingRel represents the TABLESAMPLE BERNOULLI or SYSTEM keyword applied to a table, view or subquery.

Author:

Stephan Zuercher

Field Summary

private RelOptSamplingParameters

params

Fields inherited from class org.eigenbase.rel.AbstractRelNode

digest, id, nextId, rowType, traits

Fields inherited from interface org.eigenbase.rel.RelNode

emptyArray

Constructor Summary

SamplingRel(RelOptCluster cluster, RelNode child, RelOptSamplingParameters params)

Method Summary

RelNode	clone() Clones this RelNode.
void	explain(RelOptPlanWriter pw)
RelOptSamplingParameters	getSamplingParameters() Retrieve the sampling parameters for this SamplingRel.

Methods inherited from class org.eigenbase.rel.SingleRel

childrenAccept, deriveRowType, getChild, getInputs, getRows, replaceInput

Methods inherited from class org.eigenbase.rel.AbstractRelNode

cloneTraits, collectVariablesSet, collectVariablesUsed, computeDigest, computeSelfCost, getChildExps, getCluster, getCollationList, getConvention, getCorrelVariable, getDescription, getDigest, getExpectedInputRowType, getId, getInput, getOrCreateCorrelVariable, getQuery, getRelTypeName, getRowType, getTable, getTraits, getVariablesStopped, inheritTraitsFrom, isAccessTo, isDistinct, isValid, onRegister, recomputeDigest, register, registerCorrelVariable, setCorrelVariable, toString

Methods inherited from class java.lang.Object

equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

params

private final RelOptSamplingParameters params

Constructor Detail

SamplingRel

public SamplingRel(RelOptCluster cluster,
                   RelNode child,
                   RelOptSamplingParameters params)

Method Detail

clone

public RelNode clone()

Description copied from interface: RelNode

Clones this RelNode.

Traits of the RelNode must be explicitly cloned, using AbstractRelNode.inheritTraitsFrom(AbstractRelNode), as the RelNode may have traits of which it has no knowledge. Example implementation:

     public MyRelNode clone()
     {
         MyRelNode clone = new MyRelNode(...);
         clone.inheritTraitsFrom(this);
         return clone;
     }
 

N.B.: This method must be overridden whenever an existing, concrete RelNode is extended. Otherwise, calling clone() will produce a differently typed RelNode, resulting in invalid or incorrect query plans.

Specified by:

clone in interface RelNode

Specified by:

clone in class AbstractRelNode

Returns:

a clone of this RelNode

getSamplingParameters

public RelOptSamplingParameters getSamplingParameters()

Retrieve the sampling parameters for this SamplingRel.

explain

public void explain(RelOptPlanWriter pw)

Specified by:

explain in interface RelNode

Overrides:

explain in class SingleRel